Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
/*
 * Institute DA-IICT
 */

import java.io.*;
import java.math.*;
import java.util.*;

public class A{
	
	InputStream in;
	PrintWriter out;
	
	void solve() {
		int n=ni();
		int m=ni();
		int mat[][]=new int[n][m];
		for (int i=0;i<n;i++)
			for (int j=0;j<m;j++)
				mat[i][j]=ni();
		boolean flag=false;
		if (n>m)
		{
			flag=true;
			int tmp[][]=new int[m][n];
			for (int i=0;i<m;i++)
				for (int j=0;j<n;j++)
					tmp[i][j]=mat[j][i];
			int t=n;
			n=m;
			m=t;
			mat=tmp;
		}
		
		int rmin[]=new int[n];
		int cmin[]=new int[m];
		for (int i=0;i<n;i++)
		{
			rmin[i]=mat[i][0];
			for (int j=1;j<m;j++)
				rmin[i]=Math.min(rmin[i], mat[i][j]);
		}
		
		
		int nmat[][]=new int[n][m];
		int cnt=0;
		for (int i=0;i<n;i++)
		{
			if (rmin[i]!=0)
			{
				cnt+=rmin[i];
			}
			else
				continue;
			for (int j=0;j<m;j++)
				nmat[i][j]=rmin[i];
		}
		for (int j=0;j<m;j++)
		{
			cmin[j]=mat[0][j]-nmat[0][j];
			for (int i=1;i<n;i++)
				cmin[j]=Math.min(cmin[j], mat[i][j]-nmat[i][j]);
		}
		//tr(cmin);
		//String steps[]=new String[123456];
		//int idx=0;
		for (int j=0;j<m;j++)
		{
			if (cmin[j]!=0)
			{
				cnt+=cmin[j];
			}
			else
				continue;
			for (int i=0;i<n;i++)
				nmat[i][j]+=cmin[j];
		}
		
		for (int i=0;i<n;i++)
		{
			for (int j=0;j<m;j++)
			{
				if (nmat[i][j]!=mat[i][j])
				{
					out.println(-1);
					return;
				}
			}
		}
		out.println(cnt);
		if (flag)
		{
			for (int i=0;i<n;i++)
			{
				if (rmin[i]!=0)
					{
						for (int j=0;j<rmin[i];j++)
							out.println("col "+(i+1));
					}
			}
			for (int i=0;i<m;i++)
			{
				if (cmin[i]!=0)
					{
						for (int j=0;j<cmin[i];j++)
							out.println("row "+(i+1));
					}
			}
		}
		else
		{
			for (int i=0;i<n;i++)
			{
				if (rmin[i]!=0)
					{
						for (int j=0;j<rmin[i];j++)
							out.println("row "+(i+1));
					}
			}
			for (int i=0;i<m;i++)
			{
				if (cmin[i]!=0)
					{
						for (int j=0;j<cmin[i];j++)
							out.println("col "+(i+1));
					}
			}
		}
	}

	
	void run() throws Exception {
		String INPUT = "C:/Users/ayubs/Desktop/input.txt";
		in = oj ? System.in : new FileInputStream(INPUT);
		out = new PrintWriter(System.out);
		
			long s = System.currentTimeMillis();
			solve();
			out.flush();
			tr(System.currentTimeMillis() - s + "ms");
	}
	public static void main(String[] args) throws Exception {
		new A().run();
	}
	
	private byte[] inbuf = new byte[1024];
	public int lenbuf = 0, ptrbuf = 0;
	
	private int readByte() {
		if (lenbuf == -1)
			throw new InputMismatchException();
		if (ptrbuf >= lenbuf) {
			ptrbuf = 0;
			try {
				lenbuf = in.read(inbuf);
			} catch (IOException e) {
				throw new InputMismatchException();
			}
			if (lenbuf <= 0)
				return -1;
		}
		return inbuf[ptrbuf++];
	}
	
	private boolean inSpaceChar(int c) {
		return !(c >= 33 && c <= 126);
	}
	
	private int skip() {
		int b;
		while ((b = readByte()) != -1 && inSpaceChar(b))
			;
		return b;
	}
	
	private double nd() {
		return Double.parseDouble(ns());
	}
	
	private char nc() {
		return (char) skip();
	}
	
	private String ns() {
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while (!(inSpaceChar(b))) { // when nextLine, (inSpaceChar(b) && b != ' ')
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	
	private char[] ns(int n) {
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while (p < n && !(inSpaceChar(b))) {
			buf[p++] = (char) b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}
	
	private char[][] nm(int n, int m) {
		char[][] map = new char[n][];
		for (int i = 0; i < n; i++)
			map[i] = ns(m);
		return map;
	}
	
	private int[] na(int n) {
		int[] a = new int[n];
		for (int i = 0; i < n; i++)
			a[i] = ni();
		return a;
	}
	
	private int ni() {
		int num = 0, b;
		boolean minus = false;
		while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'))
			;
		if (b == '-') {
			minus = true;
			b = readByte();
		}
		
		while (true) {
			if (b >= '0' && b <= '9') {
				num = num * 10 + (b - '0');
			} else {
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private long nl() {
		long num = 0;
		int b;
		boolean minus = false;
		while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'))
			;
		if (b == '-') {
			minus = true;
			b = readByte();
		}
		
		while (true) {
			if (b >= '0' && b <= '9') {
				num = num * 10 + (b - '0');
			} else {
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private boolean oj = System.getProperty("ONLINE_JUDGE") != null;
	
	private void tr(Object... o) {
		if (!oj)
			System.out.println(Arrays.deepToString(o));
	}
}